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Publication numberUS3647050 A
Publication typeGrant
Publication dateMar 7, 1972
Filing dateJun 11, 1970
Priority dateJun 11, 1970
Publication numberUS 3647050 A, US 3647050A, US-A-3647050, US3647050 A, US3647050A
InventorsNeal Warren D
Original AssigneeAerojet General Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Sprocket drive tensioning mount for conveyors
US 3647050 A
Abstract
A chain-type conveyor forming a continuous loop of chain is driven by a large sprocket wheel which may be several feet in diameter. Tension is applied to the chain at one side of the wheel and accordingly a slack condition may occur at the other side of the wheel. The wheel is mounted along with its power drive, such as an electric motor, in a framework having a pivot point on the tension side of the wheel so that as the wheel revolves the tension side of the wheel will tend to be swung in a direction opposite to that in which tension is furnished to the chain, as a matter of reaction. This causes the opposite side of the wheel to swing in the opposite direction thereby taking up slack in the chain leaving the wheel at that side. The distance from the pivot point about which the mounting frame of the wheel can swing to the adjacent periphery is considerably shorter than the distance from the pivot point to the opposite side of the wheel so that only such torque as is necessary for taking up slack will be provided. Means are provided for telescopic movement of the conveyor guide and chain tracks to compensate for tensioning movement of the sprocket wheel mount. On carousel tray sorters where large sprockets are required to provide tray clearance, considerable space is saved and sorter length reduced by eliminating the need for a separate takeup loop. Additionally, the construction permits convenient initial tensioning of the chain by means of a weight bias acting on the mount.
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United States Patent Mar. 7, 1972 Neal [54] SPROCKET DRIVE TENSIONING MOUNT FOR CONVEYORS [72] Inventor: Warren D. Neal, Walkersville, Md.

[73] Assignee: Aerojet-General Corporation, El Monte,

Calif.

[22] Filed: June 11, 1970 21 Appl. No.: 45,403

[52] US. Cl ..l98/203, 198/208 [51] Int. Cl ....B65g 15/30, 1365b 23/02 [58] Field of Search ..l98/203, 208; 74/242.l5 R

[56] References Cited Attomey-Edward O. Ansell, Albert M. Zalkind and D. Gordon Angus [57] ABSTRACT A chain-type conveyor forming a continuous loop of chain is driven by a large sprocket wheel which may be several feet in diameter. Tension is applied to the chain at one side of the wheel and accordingly a slack condition may occur at the other side of the wheel. The wheel is mounted along with its power drive, such as an electric motor, in a framework having a pivot point on the tension side of the wheel so that as the wheel revolves the tension side of the wheel will tend to be swung in a direction opposite to that in which tension is furnished to the chain, as a matter of reaction. This causes the opposite side of the wheel to swing in the opposite direction thereby taking up slack in the chain leaving the wheel at that side. The distance from the pivot point about which the mounting frame of the wheel can swing to the adjacent periphery is considerably shorter than the distance from the pivot point to the opposite side of the wheel so that only such torque as is necessary for taking up slack will be provided. Means are provided for telescopic movement of the conveyor guide and chain tracks to compensate for tensioning movement of the sprocket wheel mount. On carousel tray sorters where large sprockets are required to provide tray clearance, considerable space is saved and sorter length reduced by eliminating the need for a separate takeup loop. Additionally, the construction permits convenient initial tensioning of the chain by means of a weight bias acting on the mount.

20 Claims, 11 Drawing Figures PATENTEUMAR H972 I 3,647,050

sum 1 or 6 INVENTOR WARREN 0. NEAL WMf ATTORNEY PATENTEDMAR 7 1972 SHEET 2 UF 6 PATENTEDHAR 1 me In nr no r71 m a:

SHEET 3 OF 6 FIG.3

PATENTEDMAR 7 I972 3, 647. 050

sum 5 OF 6 m wE SPROCKET DRIVE TENSIONING MOUNT FOR CONVEYORS Briefly, the invention comprises a fixed base frame, generally mounted at an elevation above a floor as on pedestals. The frame supports a drive sprocket wheel and mount means therefor, for automatically tensioning a chain passing around the wheel and which chain motivates a series of tiltable trays in a conveyor system. The overall system of a tray type conveyor of the kind in which the present invention is usable is shown in assignees previously filed application of Wooten, Neal, and Einfeldt, Ser. No. 2,638, filed Jan. I3, 1970. However, the invention disclosed herein is of general application in any chain drive system.

The invention herein utilizes components such as a carriage which carries the sprocket wheel and is rollably mounted on the fixed base so that it can be biased as by a weight to maintain predetermined minimum tension in the sprocket chain driven by the wheel. The wheel is mounted on the carriage by a mounting means which comprises a pivotal frame having a hearing which rotatively supports the wheel and which frame also carries the electric motor and gear reduction for the wheel. A pivotal connection is provided intermediate the wheel carrying frame and the carriage which pivotal connection has an axis much closer to the upstream or tension side of the wheel then to the downstream or slack side of the wheel. The frame is suitably supported by rollers engaging the carriage so that the frame can swing about the pivotal connection and thus bodily carry the wheel to apply tension at the downstream side of the sprocket chain in response to tension existing in the upstream side.

A detailed description of the invention now follows in conjunction with the appended drawing in which:

FIG. I is a plan view of the general layout of the sprocket wheel drive for a tray conveyor of the carousel type;

FIG. 2 is an elevation taken generally through 22 of FIG. 1;

FIG. 3 is an elevation taken generally through 3-3 of FIG.

FIG. 4 is a plan view showing detailed structure of the pivoting mount means arrangement for the sprocket wheel;

FIG. 5 is an elevation showing essential elements as seen in FIG. 4, viewed in the same direction as the view in FIG. 2;

FIG. 6 is an end view again showing essential elements of the pivotal structure viewed in the same direction as the view of FIG. 3;

FIG. 7 is an enlarged plan view of the downstream side of FIG. 1 showing the articulation of the movable track assem'bly portion which curves around the sprocket wheel and is carried by the sprocket wheel mount means, and a portion of the fixed, i.e., stationary, track assembly;

FIG. 8 is a section through 88 of FIG. 7;

FIG. 9 is a section through 99 of FIG. 8;

FIG. I0 is a section generally through 10-10 of FIG. 7; and FIG. 11 is an end elevation thereof.

FIG. 10 is a section generally through 10-10 of FIG. 7, and FIG. 11 is an end elevation thereof through llll of FIG. 7.

In FIGS. I and 2 the invention is diagrammatically illustrated and will be seen to comprise a fixed base 10 which supports a carriage 15 having a pair of V groove rollers at one side and smooth surfaced rollers at the other side. The V rollers 20 roll on inverted V tracks and therefore effect a fixed lineal guide for movement of the carriage, the tracks being suitably secured to the fixed base 10. The rollers 25 are simply rolling supports for the other side of the carriage. The carriage has reversible linear freedom of movement in the directions of arrow A.

A sprocket wheel mounting means comprising a frame which carries sprocket wheel bearing 38 is pivotally secured to the carriage as by a pivotal connection pin means 40 and the axis P of such pivotal connection is approximately one-tenth of the distance from the upstream of tension side of the sprocket wheel W (shown in phantom in FIG. 1) as it is from the downstream or slack side 50, as measured on a diameter normal to the direction of freedom of the carriage 15. The

wheel mounting means 35 is supported for pivotal motion at one side only at the pivotal mount 40 and on its opposite side by rollers 55 rotative on respective axes 46 and 47, in a horizontal plane, which pass through the vertical axis P of pivotal mount 40.

Accordingly, it can be seen that a counterclockwise swinging movement of the sprocket wheel mounting means 35 about axis P will bodily and pivotally carry the sprocket wheel on the arc indicated by arrow B having P as its center, causing tension in the downstream side of sprocket chain C. Such movement is caused by the load tension at the upstream side of the chain, the sprocket wheel rotating clockwise, arrow F.

The sprocket wheel is rotatively supported on mounting means 35 by bearing 38 having base disc 65 secured to the frame and the mounting means 35 also carries the electric motor 70 and gear reduction drive 75 having drive sprocket 77, the sprocket wheel W being driven via the chain and coaxial sprocket 82 connected by collar 85. Base disc 65 of bearing 38 is riveted or otherwise fastened to the framing of mount means 35, as later described, all as apparent in FIGS. 1 and 2. Thus, the entire assembly comprising the sprocket wheel and its motive power components can pivot as a unit about axis P.

Sprocket chain C encompasses the wheel will the usual manner and cargo trays T may be connected as shown in Ser. No. 2,638.

In order to effect a predetermined minimum tension in the chain a cable 93 (FIGS. 1-3) is attached to a weight 95 and connected to the mounting means 35 at 97, to bias the sprocket wheel in a direction leftward (FIGS. 1 and 2) to effect any desired amount of initial tension in chain C. The weight 95 is housed in a vertical chute 98, cable 93 passing over a pulley carried by the stationary components of a fixed support frame F (FIGS. 2 and 3). Portions of the fixed support are designated with ground symbols for clarity.

From the above description it will be apparent that tension in the upstream side of the chain at point of entry 45 will cause bodily movement of the sprocket wheel around the axis P in a counterclockwise direction and this will effect a tension in the downstream side of the chain at 50 to maintain any degree of tension designed into the system dependent upon the ratio of distances between axis P and the wheel periphery measured to the points 45 and 50. Further, the cost of a conveyor sorter means in accordance with the invention is reduced due to reduction in sorter length by combining the drive and the sprocket chain takeup into a single assembly as compared with a separate drive assembly and a separate takeup assembly.

The various subassemblies indicated by the reference numerals l0, 15, 35 and 40 are comprised of certain structural elements now to be generally described. Thus, the pedestal base 10 has vertical column members such as 105, suitably cross braced by members 107, as shown in FIG. 2, and carrying parallel horizontal joists such as (FIGS. l-3) wherein each joist is suitably fastened at the top of a respective pair of columns 105, such as by welding or the like. The joists carry guard hoods 112a and 11211 of channel iron over respective rollers 20 and 25. Pulley 100, over which the cable 93 for weight 95 passes, is secured to the web of hood 1I2b via intermediate spacer channels 113.

Preferably the rollers 25 roll on wear strips 115 (FIG. 3) in the guard hoods, the hoods insuring against tilting of the sprocket wheel assembly out of a substantially horizontal plane.

Each joist at its outer end (FIG. 2) has a coarse adjustment screw I20 passing therethrough with a takeup nut 123 therefor; and each screw passes through a respective bracket secured to the carriage 15. Accordingly, by adjusting the screws 120, the carriage 15 can be moved to the right as seen in FIG. 2 for permitting slack in the chain so as to remove chain links and/or trays when necessary. Both screws I20 are utilized for such purpose and takeup by means of the screws is then effected after such work has been accomplished to place carriage 15 in a fixed position during conveyor operation.

The carriage is supported on rollers by means of a longitudinal frame member 138 and also is supported on rollers by means of a parallel longitudinal framing member 144. The framing members are parallel to joists 110 of the fixed frame, as seen in FIG, 1, and have stub axles for the rollers 20 and 25, as indicated at 146 (FIG. 1). Cross frame members such as 148 and 152 connect the longitudinal frame members 138 and I44 and are suitably welded therebetween. All frame members can be bars, channels or angle irons, etc., and member 144 is extended to support the outer end of a diagonally disposed cleat 154 having an angle iron segment 156 to support a roller 55 of mount means 35, segment 156 also being secured to member 144, and the top edge of the angle iron flange supporting roller 55, as shown. Similarly, an angle iron segment 156 supported across frame members 144 and 148 supports the other roller 55.

The sprocket wheel mount comprises aligned track support tubular members 160a and 16% transversely fastened to respective parallel longitudinal tubular framing members 170 having intermediate welded cross members 180. Spacer bars 183 (FIG. 3) are secured on top of members 170 having angle irons 185 and 185a on respective spacer bars, thus fastened to the framing members 170, and strongly braced with diagonal angle iron members, such as 190, between additional angle irons 185b, 1856 and cross member angle irons such as 185d and 1852, to form a rigid square frame to which bearing base 65 is attached on members 190.

An electric motor and gear reduction drive support structure 210 is suspended between the frame members 170 (FIGS. l-3) comprised of a boxlike configuration having vertical angle irons such as 215, horizontal angle irons such as 220, diagonal bracing such as 225, and outboard brace 228 secured to member 160b, all for the purpose of effecting very firm support for the motor 70 and gear reducer 75 via platforms such as 230 and 235 mounted on cross frame angle irons 240 and 243 secured to the vertical angle irons.

Referring to FIGS. 4, 5 and 6, the structure for supporting pivotal movement of the sprocket wheel mount means 35 is illustrated and in particular FIG. 4 shows in plan the tubular member 160b extending from the longitudinal frame member 170 and braced by the diagonal member 270, which is fastened intermediate member 170 and member 16%. Further bracing is afforded by member 228 heretofore mentioned and shown in FIGS. 4, 5 and 6. A pair of plates 273 and 276, as seen in FIGS. 5 and 6, are carried on gussets 280 and 284 wherein gusset 280 is suitably welded intermediate members 138 and 276 and gusset 284 is also welded between member 138 and member 276. The plate construction is thus very strongly built in an all welded structure wherein plate 276 is welded to the gussets and plate 273 is bolted as by bolts 288 to plate 276. On plate 273, there is a thrust bearing 292 surmounting which is a plate 294. Pivotally contiguous with plate 294 is a plate 300 which is welded to the sprocket wheel mount 35, at the bottom of the diagonally disposed frame member 270 (see FIG. 1) and also at the bottom of the extending frame member 16%. The frame member 270 is welded to the side of frame member 170 at one end and to frame member 16% at the other end. Thus a very strong triangular framework is provided for the plate 300 since it supports one side of the swinging frame or mount means 35 via the thrust bearing 292. A bolt 310 passes through the plates and the thrust bearing to form,a pivot or pintle on which the entire mount means 35 can swing about the bolt which effects the axis P.

The other side of mount means 35 is carried by rollers 55 on angle iron members 156, as heretofore mentioned, and as seen in FIG. 1, the rollers are carried on a frame member 170 by respective suitable welded outboard attached plate structure indicated generally at 315.

Inasmuch as the sprocket wheel mount means 35 swings on the bolt 310 as a pivot in order to increase tension in the chain, and further since it may be necessary to slack off on both sides of the chain via screws 120 for maintenance work,

it is desirable to provide some means of expanding or contracting the connections between the bodily movable tracks that go around the sprocket wheel and move as the wheel is bodily moved, in relation to the fixed portion of the tracks leading to and coming from the sprocket wheel.

This is preferably arranged by mounting the sprocket wheel encompassing arcuate portions of the tracks on the sprocket wheel mount means 35 and providing articulated sliding and/or pivotal connections to the fixed portions. Thus, referring to FIG. 1, the outsidemost arcuate track 350 having stationery portion 350a is the equivalent of track 15 as disclosed in Ser. No. 2,638 and is preferably a channel open at its radial inner side for the outer wheels of the trays where it goes around the sprocket wheel. It is supported vertically at the points marked with an X vertically thereabove at the ends of the frame members 170. It is also supported at its ends at respective ends of frame members a and 16%. The next outermost arcuate track 360 having stationary portion 360a is supported at the points marked X vertically thereabove on the frame members lying directly therebelow, namely frame members 170, 160a and 160b. This is the track for the actuator cam, i.e., the tray tilting roller 132 shown in Ser. No. 2,638, FIG. 3. Thus, track 360 is the equivalent of track 35 in Ser.

No. 2,638 and is, as in the previous application, shown as a channel open at the top for the tray actuator rollers to extend thereinto in order to ensure that the trays will remain horizontal as they go around the sprocket wheel.

The rigid connection between each tray and the drive chain is normally sufficient so that a plain flat track can be used for the outermost track, but a channel, open at the inner side is preferred to avoid possible mishap if some unbalanced forces should cause the trays to rock transversely in going around the sprocket wheel.

There is no need for any arcuate continuation of stationary track 380 for the innermost wheels of the trays. As seen in Ser. No. 2,638 (FIG. la, tracks 10) track 380 stops short of the sprocket wheel at both entrance and exit of the sprocket wheel. The innermost wheels simply pass over the sprocket wheel in going therearound, being unsupported, since the remainder of the tray, chain, and other structure is sufiicient to hold the trays level along with their carriages.

The present invention provides for an actuation of telescopic joints for the tracks at the upstream and downstream ends of the sprocket wheel, as will be later described to ensure proper alignment of the tray wheels and tray actuating roller to and from the sprocket wheel when the sprocket wheel swings with support means 35 in automatically tensioning the chain.

The chain itself goes around the sprocket and therefore requires no guide.

Referring to FIGS 2 and 3, it will be noted that arcuate track 350 is supported on a combination of angle members generally designated as 385 and 385a, as exemplary, which will be understood to be secured to frame members 170, 160a and 160b, respectively. Track 360 rests on plates and angle iron supports generally designated as 390 and 3900 for support. It will be understood that angle iron support constructions just described appear at the various points marked X on FIG. 1, and are only exemplary. It will likewise be understood that the stationary portions of the track are supported in the conveyor loop in any suitable manner, e.g., as in Ser. No. 2,638.

From the preceding it will be apparent that as the chain tension at point 45 on the sprocket wheel (FIG. 1) causes the entire sprocket wheel 35 to bodily rotate around the axis P of the bolt 310, the arcuate tracks will swing around the same axis. However, the various rollers in the arcuate tracks must enter and leave those tracks from and to the fixed track portions. Also, the innermost wheels of the trays should leave the respective fixed track portions and reenter thereon properly aligned. While the need for pivotal and telescopic transition elements need not be essential for a workable conveyor system not of massive construction nor for heavy-duty cargo handling, e.g., the simple arcuate track arrangement in Ser. No. 2,638 would be feasible without pivotal and telescopic track elements, the present invention provides such elements where conveying systems are huge, trays are massive and cargo up to 300 pounds per tray is carried.

Referring to FIGS. 7-11, and reference being made to FIG. I for the overall plan view, a description of the pivotal and telescopic articulated connections between the movable arcu ate track portions around the sprocket wheel and the stationary portions at both sides of the wheel will now be explained as to such essentials thought novel so that persons skilled in this art will readily understand the construction. The illustration is exemplary only and details of routine structural engineering, fastenings, bracings, shimming, leveling, etc., etc., are omitted as being conventional and matters of designers choice and knowledge.

Inasmuch as the connections are the same at both sides of the sprocket wheel, being substantially mirror images of each other, only the connections for the downstream side of the wheel will be described in detail, except that at the upstream side, as seen in FIG. 1, the articulated connection later described for track 380 is supported on member 270 instead of member 160b, but essentially the structures are the same.

In FIGS. 1 and 7-I0 the Roman numerals I, II and III indicate pivotal track connections for, respectively, as shown in phantom in FIG. 9, the outer wheels WO of the trays, the tilting actuator rollers R of the trays, and the inner wheels WI of the trays, in the general configuration of Ser. No. 2,684, FIG. 10.

The pivotal connection I (FIG. 9) joins arm 400 comprised of angle iron (FIG. 8), having a surface plate 405 secured thereto, with the arcuate track 350. Thus, arm 400 is connected via a link 408 pivotally connected to the arm 400 at 408a (FIG. 9) and to the arcuate track section 350 at 408b. Wheels leaving track 350 will roll on plate 405 to the stationary track 350a, the pivotal structure being supported by welded or bolted angle iron construction secured to member 16011, e.g., angle iron pieces 4090, 409b, 4090. The member 409C is welded to the bottom flange of track 350, and member 409a is welded to member 1600.

Pivot 408b is carried by angle iron member 4090. The entrance end of track 350a is supported on angle iron members such as 420, 4200, 425a, 425b, the latter two being transversely carried by the framework support of the conveyor in any suitable manner (not shown) to support track structure at the junctions. The horizontal flange of arm 400 slides on the support surface comprising angle iron members 435a and 435b. Member 435a extends from member 425a to a vertical column 400 and member 435 is secured to member 4350 (FIG. 8) via a spacer bar 4350 between the vertical flanges. The vertical flange of arm 400 can slide in the spacing 435d thus provided. The wheels WO actually roll through a drop of a small fraction of an inch due to the thickness of arm 400 and plate 405 onto the horizontal flange of member 435a. The outboard comer of member 435a is carried on angle iron member 442 supported on member 425a and fitted into a notch of the end of a track segment 445 of track 3500 to form a flush surface at 445a. The segment 445 can be a separate short track for assembly convenience, as indicated by the additional abutted flush joint 448 supported in angle iron 450 on member 425b.

The geometry of arm 400, link 408, plate 405, members 435a and 435b, and the spacing 435d, will be understood to be such that regardless of any swung position of sprocket wheel mount means 35, arm 400 will slide by reciprocal guidance in spacing 435d actuated via the link 408 with sliding movement on member 4350. Arm 400 is thus motivated by swinging of track 350 around axis P (FIG. I), to provide a path over which the outer wheels WO of the trays can run between the movable and the stationary track portions, 350 and 350a respectively.

In a similar manner the arm 460, the upstream counterpart of arm 400, is linkage connected with the upstream end of arcuate track 350 to effect a path over which the outer wheels of the trays can roll from the stationary to the arcuate movable track portion.

The pivot means Il (FIG. 9) intermediate the tray tilting roller guide channel track components 360, 360a, comprises a pivot arm 465 pivoted to the arcuate movable track portion 360 at 46511 and welded to a short track section 470 at 465b so that it can slide upon actuation by arm 465 as track 360 swings. A telescopic joint 475 effects alignment in any position of track section 470. The telescopic joint is provided by spaced angle irons 480 carried by members 425a and 425k. Sufficient play in the telescopic joint is provided so that even when the section 470 is in any angularly related position there will be no binding or jamming, section 470 being slidably movably supported on member 425a.

The pivot means III (FIGS. 7, 8 and l0) comprises a channel 486 (also see FIG. I) open at the outer side pivotally connected to the frame member 106a.

The pivotal structure comprises a pintle 497 carried between bars 497a and 4971) welded top and bottom, respectively, to member 1600 with an intermediate vertical plate 497e, welded therebetween and to member a. The pintle is pinned in place as shown, as by pins such as 497d and has a rotative collar 497e therearound to which is welded a channel support arm 497f extending downstream to a vertical brace 497q secured thereto and welded to channel 486 for support thereof.

The channel 486 leads to the telescopic joint 500 comprising two sets of interdigitated bars within one set, i.e., alternate bars 510, connect to the fixed track portion 380 being spacedly welded thereon to a horizontal flange 520. The other set of alternate bars 530 are spacedly welded to the bottom flange 535 of the channel 486. The bottom flange 535 is cut away from point 540 to the end of the channel 486 so that the top edges of bars 510 can be flush with the flange 535 for smooth transition of wheels WI. Bars 530 are slidably supported on flange 520 and notched at 540 to be top flush with bars 510. Thus the two sets of interdigitated bars form an extensible and contractable flush track surface, flush with flange 535 and track 380, over which the inner wheels WI of the trays can roll from the channel 486. This type of sliding bar joint is believed preferable as a telescopic connection rather than the sliding plate joint 405 used for the outer wheels because the flush surfaces of the bars and tracks provide a smoother transition of the rolling wheels.

The spacing of the bars of each set is close enough to provide ample surface support for the rolling wheels, and where the bar sets overlap, at about the center of the configuration, the wheel support surface has no gaps except for the designed tolerance necessary to allow linear movement of bars 530 upon actuation by pivot 497 as support means 35 swings. The axis of pivot 497 is located (FIG. 1) so that the motion path of bars 530 is practically tangential to sprocket wheel W and, accordingly, no significant angular motion of movable bars 530 is met which might cause undue friction or jamming in sliding relative to fixed bars 510.

The upstream side of sprocket wheel W has the same telescopic joint and pivot structures as I, II and III, just described the only difference of any structural significance being that the support for the pivot of the track 380 is on member 270, the bars attached thereto which are equivalent to bars 497a and 497b, being shorter and angularly disposed due to the geometry of the structure.

Depending upon the type of chain used, a chain guide upstream and downstream of the sprocket wheel is desirable and such a guide has been indicated in FIG. 7 at 560 for the downstream portion of sprocket wheel W. A chain guide such as 560 or any other types of chain guides may of course be suitably secured to any fixed portion of the fixed track supporting structure or to one of the fixed tracks, as a matter or choice and design.

From the foregoing, it will be apparent that the invention provides in a conveyor system a tak-up mechanism responsive to torque load wherein the drive wheel, for example a sprocket wheel or a belt pulley, is bodily moved by virtue of reaction force, It will be noted that the invention is not necessarily restricted to tension type driven members such as chains, belts or the like, but could also be used in precisely the same application of principle and substantially the same construction and arrangement for compression types of drive. This will be readily apparent to persons skilled in the art, who will recognize that suitable relocation of pivotal mount 40 effects slack take up at point 45 (FIG. 1) when torque load reaction is applied at 50.

What is claimed is:

1. in a conveying system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising a horizontal drive wheel and drive wheel mount means for said drive wheel effecting rotary support for said drive wheel and providing a vertical axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about a vertical axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; a chain around said drive wheel motivated thereby in a horizontal plane and cargo-carrying members connected to said chain and driven thereby; including support means for said cargo carrying members disposed for support thereof in passing around said drive wheel.

2. In a conveying system, a tensioning and slack take up mechanism for a chainor belt-type driven member comprising a drive wheel and drive wheel mount means for said drive wheel effecting rotary support for said drive wheel and providing an axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; said system including track means having a track at least partially encompassing said drive wheel; means whereby said track is bodily movable about said latter axis with said drive wheel; said track means also having a relatively fixed track extending from said mechanism; including actuatable track connection means disposed intermediate the encompassing track and the fixed track comprising an actuating connection coupled with said drive wheel so as to be actuated for effecting a path between the encompassing track and the fixed track when said drive wheel has bodily pivotal motion.

3. ln a system as set forth in claim 2, said actuatable track connection means comprising a telescopic joint joining the encompassing track with the fixed track and having an intermediate track member having substantially linear movement as said drive wheel is bodily pivoted.

4. In a system as set forth in claim 3, wherein said actuating connection comprises a pivotal joint; said pivotal joint being disposed with respect to said drive wheel so as to exert approximately tangential thrust in the direction of linear movement of said telescopic joint, said telescopic joint having sufficient transverse play to effect substantially linear movement at any angular orientation of said pivotal joint.

5. In a system as set forth in claim 4, wherein said telescopic joint comprises a pair of suitably spaced guide members fixedly secured to said fixed track, said track member being slidably disposed between said guide members during bodily pivotal movement ofsaid drive wheel.

6. In a conveying system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising a drive wheel and drive wheel mount means for said drive wheel effecting rotary support for said drive wheel and providing an axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; including a fixed track for a tray to be motivated by said driven member; and means for connecting said fixed track to said pivotal device comprising a telescopic joint having a set of bars actuatably connected thereto and interdigitated with a set of bars secured to said fixed track; and means supporting said sets of bars so that the top edges thereof are substantially flush.

7. In a conveying system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising a drive wheel and drive wheel mount means for said drive wheel effecting rotary support for said drive wheel and providing an axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; said drive wheel mount means comprising a reciprocal carriage and said pivotal device comprising a frame pivotally secured thereto, means biasing said frame in a direction to effect a predetermined tension in a driven member encompassing said drive wheel, said drive wheel being carried on said frame.

8. In a system as set forth in claim 7, said frame having support on said carriage at said pivotal means and coaxially therewith at one side of said drive wheel and said frame having spaced roller means effecting roller support on said carriage at the other side of said drive wheel.

9. In a system as set forth in claim 8, wherein said predetermined distance is closer to the upstream portion of said wheel than to the downstream portion whereby an increment of bodily motion of said wheel effected by tension in said driven member produces a larger increment of motion at the downstream portion of said wheel.

10. In a system as set forth in claim 7, including means for powering said drive wheel comprising an electric motor, and said electric motor being carried by said frame.

11. In a conveying system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising a drive wheel and drive wheel mount means for said drive wheel effecting rotaty support for said drive wheel and providing an axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; said pivotal device comprising a drive wheel support structure having a pivotal connection means for attachment to a relatively fixed member at an upstream side of said structure and having spaced support means comprising rollers at the downstream side of said structure and adapted to roll on a relatively fixed surface, said rollers having axes intersecting the axis of said pivotal connection means.

12. In a conveying system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising a drive wheel and drive wheel mount means for said drive wheel effecting rotary support for said drive wheel and providing an axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; said mount means comprising a carriage supported for reciprocal motion and said pivotal device being carried thereon and pivotally connected thereto; a base on which said carriage is movable for translating said drive wheel to effect initial tension in a driven member and for positioning said drive wheel to effect slack in said driven member for maintenance work and the like; adjustable screw means intermediate said carriage and said base for effecting a predetermined positioning of said carriage; weight bias means connected to said pivotal device for effecting bias on a driven member to exert tension therein; said weight bias device comprising a weight and a cable suspension therefor having pulley support on said base.

13. In a conveyor system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising a drive wheel and drive wheel torque responsive means providing rotary support for said drive wheel on an axis on which said drive wheel is rotative for exerting torque to effect drive tension in a driven member; and providing support whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel; wherein said driven member is for the motivation of a plurality of trays having side rollers and a tilt actuating roller; and arcuate channel track encompassing the rotational axis of said drive wheel for receiving outer rollers of trays in moving around said drive wheel; an inwardly disposed arcuate channel track coaxial with said first mentioned channel track for receiving tray actuating rollers; said two tracks extending substantially from an upstream to a downstream side of said drive wheel; respective fixed tracks for connection to said arcuate tracks; and connection means for connecting said arcuate tracks to respective fixed tracks of a conveyor system, and means whereby said arcuate tracks are bodily pivotal with said drive wheel.

[4. ln a conveyor system as set forth in claim 13, including an additional fixed track disposed at the upstream and downstream side of said drive wheel and inwardly disposed of the aforementioned fixed tracks for receiving inner rollers of trays; said connection means extending from said fixed tracks to said torque responsive means; said connection means comprising actuatable track segments to effect paths for all said rollers to and from said fixed tracks for trays passing around said drive wheel.

15. In a conveyor system as set forth in claim 14, all said track segments having pivotal connection to said torque responsive means for actuation thereby and being telescopically connected to respective fixed tracks.

16. In a conveyor system, a drive wheel and a driven means motivated thereby having a force receiving flight and a return flight; a pivotal mount for said drive wheel responsive to torque load on said drive wheel to bodily pivot said drive wheel in a direction to reduce slack in said return flight; including a first track means connected thereto, said first and second track means having relative motion when said drive wheel has pivotal movement; and connection means connecting said first and second track means having relative motion with res pect to said first and second track means to effect a continuing path therebetween when relative motion between said first and second track means occurs.

17. In a conveyor system, a drive wheel and a driven means motivated thereby having a force receiving flight and a return flight; a movable mount for said drive wheel responsive to torque load on said drive wheel to bodily move said drive wheel in a direction to reduce slack in said return flight; including a first track means bodily movable with said drive means, and a second track means connected thereto, said first and second track means having relative motion when said drive wheel has bodily movement; and connection means connecting said first and second track means having relative motion with respect to said first and second track means to effect a continuing path therebetween when relative motion between said first and second track means occurs.

18. A pivotal device for carrying a drive wheel to be bodily pivoted in response to tension in a driven member at an upstream side, for increasing tension in a driven member at a downstream side; track means fixedly secured to and extending between the upstream and downstream sides of said pivotal device; track means arcuately encompassing said pivotal device and means effecting actuatable segmental track sections between said arcuate track means and respective fixed tracks affording continuous paths for elements of trays motivated by said driven member, said track segments being connected to said pivotal device for actuation so as to effect said paths at any pivoted position of said pivotal device.

19. A tensioning device for a sprocket wheel, comprising a fixed base; a carriage on said base and moveable thereon to effect initial tension in chain means to be driven by said wheel; sprocket wheel support means on said carriage and a sprocket wheel rotatively carried by said support means; a pivotal connection between said support means and said carriage; the pivotal axis of said pivotal connection being disposed offside of the rotative center of said wheel whereby tension in a chain means entering said wheel causes pivotal movement bodily of said wheel around said pivotal connection to maintain tension on said chain means leaving said wheel.

20. [n a conveying system, a tensioning and slack takeup mechanism for a chainor belt-type driven member comprising: a drive wheel and drive wheel mount means for said drive wheel effecting rotary support for said drive wheel and providing an axis on which said drive wheel is rotative for exerting drive tension on a driven member; a pivotal device having means whereby said drive wheel is bodily pivotal about an axis disposed at a predetermined distance from the rotative axis of said drive wheel; whereby load tension force effected on said drive wheel by a driven member at an upstream portion of said drive wheel effects bodily pivotal motion thereof about said pivotal axis to increase tension and take up slack in said driven member at a downstream portion of said drive wheel, including telescoping track means for connection between said pivotal device and a fixed track of a conveyor system and comprising two sets of interdigitated relatively slidable bars; means whereby one set of said bars has a pivotal connection with said pivotal device; means whereby the other set of bars is secured to said fixed track; means supporting said sets of bars so that the top edges thereof are substantially flush and form a smooth transition path to said fixed track.

Patent Citations
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US2578871 *Jul 15, 1946Dec 18, 1951Arrow ProductsPower tension elevating device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3880298 *Jul 24, 1972Apr 29, 1975Rapistan IncSorting conveyor control system
US4759438 *Jun 5, 1986Jul 26, 1988Auto-Veyor, Inc.Method of and apparatus for adjusting the length of chain conveyors and the like to accommodate for elongation or contraction thereof resulting from variations in load, wear, resiliency, tension and similar factors
US6585109Jun 18, 1999Jul 1, 2003Wf Logistik GmbhReturn device
US6860383 *Mar 6, 2003Mar 1, 2005Rapistan Systems Advertising Corp.Positive displacement sorter
US7117988Feb 11, 2005Oct 10, 2006Dematic Corp.Positive displacement sorter
US7513356Apr 30, 2008Apr 7, 2009Dematic Corp.Positive displacement sorter
EP1127485A2 *Feb 21, 2001Aug 29, 2001Fujii Shokai Co., Ltd.Feed carrying apparatus
WO1999065802A1 *Jun 18, 1999Dec 23, 1999Beyer Rolf PeterReturn device
Classifications
U.S. Classification198/815, 198/816, 198/838
International ClassificationB65G23/44, B65G23/00
Cooperative ClassificationB65G23/44
European ClassificationB65G23/44